Archive for recycling

waste tide

Posted in Books, pictures, Travel with tags , , , , , , , , , , on April 11, 2021 by xi'an

I presumably bought this book upon a suggestion made by the Amazon AI. It sounded quite original and interesting. And translated by Ken Liu. I had not seen the above cover, but it would have only helped. (And reminded me of the daunting and bittersweet Tales from the Loop.)

“None of this, of course, existed in the digital world. In their place were highly abstract algorithms and programs that turned the complicated messy world into a set of mathematical models and topological spaces. Like a real spiderweb, the web would be deformed by any insect that got caught into it, and the rate at which such deformation evolved exceeded the rate at which information might be transmitted under the restricted-bitrate regulations. In this world, the shortest path between two points was no longer the straight line.”

Waste Tide is immensely puzzling and definitely interesting. A Chinese form of Neuromancer…. With further links to the Windup Girl. The location of the novel is a near-future island in Guiyu, China. Where the World electric waste ends up, to be processed and recycled by “waste people”. Who are despised by the original inhabitants of the island. And exploited by clans and American companies. Several of the main characters find themselves torn between several cultures, but these characters often sound a bit too caricaturesque. Just like the take-over of a “waste girl” by a residual AI is somewhat clumsy. Far from the constructs of Neuromancer or Windup Girl.

Another interesting side of the book is the translation by Ken Liu, who also translated The Three Body Problem. As well as published short stories of his own. The preface warns about the multiple languages co-existing in China, beyond the most well-known Cantonese and Mandarin and the book includes footnotes about the proper pronunciation of some words.

garbage in the air

Posted in pictures, Travel, Wines with tags , , , , , , , , , , on November 6, 2019 by xi'an

As I am flying today to Seoul, for the Fall meeting of the Korean Statistical Society, a somewhat interesting paper in the New York Times about switching to alternatives for airline catering (if not air travel), starting with the figure that a passenger generates on average 1.5kg of waste per flight. And pointing out the conflicting issues in recycling food waste in most countries as they see it as imported waste and potential imported pathogens.and biohazards… While getting rids of plastic items is a tiny step in the right direction, especially because airlines do not sort between different kinds of garbage, a major step would be to avoid replacing them by another disposable item, especially heavier ones. From getting rid of providing food and drink (except water) on short and medium-haul flights to aim at healthy foods that do not require packaging or utensils. Like fruits. And asking passengers to carry their own garbage when leaving the plane could also enhance the realisation of the amount of garbage they thus produced. (On a recent early morning flight between Paris and Birmingham, the plane supposedly could not leave until the late delivery truck had brought croissants and drinks, as if passengers could not have abstained for the 55mn the flight lasted, especially when most of them were sleeping…) Nowadays. I usually travel with a water bottle that I fill before boarding after security and often skip meals on flights, but it invariably proves difficult to ask flight attendants to use my own reusable cup rather than a single-use plastic cup.

unbiased product of expectations

Posted in Books, Statistics, University life with tags , , , , , , , , on August 5, 2019 by xi'an

m_biomet_106_2coverWhile I was not involved in any way, or even aware of this research, Anthony Lee, Simone Tiberi, and Giacomo Zanella have an incoming paper in Biometrika, and which was partly written while all three authors were at the University of Warwick. The purpose is to design an efficient manner to approximate the product of n unidimensional expectations (or integrals) all computed against the same reference density. Which is not a real constraint. A neat remark that motivates the method in the paper is that an improved estimator can be connected with the permanent of the n x N matrix A made of the values of the n functions computed at N different simulations from the reference density. And involves N!/ (N-n)! terms rather than N to the power n. Since it is NP-hard to compute, a manageable alternative uses random draws from constrained permutations that are reasonably easy to simulate. Especially since, given that the estimator recycles most of the particles, it requires a much smaller version of N. Essentially N=O(n) with this scenario, instead of O(n²) with the basic Monte Carlo solution, towards a similar variance.

This framework offers many applications in latent variable models, including pseudo-marginal MCMC, of course, but also for ABC since the ABC posterior based on getting each simulated observation close enough from the corresponding actual observation fits this pattern (albeit the dependence on the chosen ordering of the data is an issue that can make the example somewhat artificial).

plastic oceans

Posted in Kids, pictures with tags , , , , , , , , on May 28, 2018 by xi'an

conference carbon footprint

Posted in Kids, pictures, Running, Travel, University life, Wines with tags , , , , , , , , , on August 1, 2017 by xi'an

As a local organiser of the recent BNP 11 conference in Paris, and hence involved in setting and cleaning coffee breaks and [now famous] wine&cheese poster sessions, I was rather shocked by the amount of waste generated by those events, albeit aware of the importance of the social exchanges they induced… And thus got to wonder how the impact of those conference events could be reduced. One solution is the drastic one, namely to provide exactly nothing at all during the breaks between talks and expect anyone hungry or thirsty enough to bring one own’s food or drink. Another one, as suggested by my daughter at the dinner table, is to provide Ecocups, namely reusable plastic glasses that can given to all participants at the beginning of the conference. Or sold (or rented) to those who have not brought their own mug or bottle. (Of course, this may be a poor idea in that manufacturing and shipping a hard-plastic glass that most likely will be discarded after a few days may be more damaging than producing the equivalent number of “disposable” thin plastic glasses. And in the end all this agitation is peanuts compared with the impact of flying participants to the conference. For which I have no handy solution… As biking to the conference location is a privilege very few can enjoy.) Still, and even though this puts another stone in the already rocky organisers’ garden, I wish we could adopt more positive policies at the meetings we organise and sponsor.